Cable force adjustment

ABSTRACT

A method includes transmitting an instruction to a motive power supply of an elastically deformable device to drive the elastically deformable device in accordance with a drive setting; measuring a force exerted on the elastically deformable device with a sensor; outputting an observed value representative of the force; comparing the observed value with a reference value corresponding with a predetermined force to be exerted on the elastically deformable device; and adjusting the drive setting based on a determination that the observed value is outside of a predetermined range of the reference value. The method prevents slack in the elastically deformable device over time. Related apparatuses, systems, techniques and articles are also described.

BACKGROUND

The field of this disclosure relates to cable force adjustment, whichmay be used in the fields of sensors, analytics, signal processing,machinery diagnostics, condition monitoring, and related disciplines.Remote borescope inspection tools are utilized to identify and/orpredict equipment failures in the field of industrial equipment inindustries such as aerospace, power generation, oil and gas, automotive,food and beverage, and pharmaceutical manufacturing. For example,borescope inspection tools are used to inspect pumps, motors,generators, pulp and paper rollers, gear boxes, pipes, tubes, puritypipes, compressors, large pistons, chillers, valves, gun barrels, mortartubes, vehicles, shipping containers, and maritime surveying structures.

SUMMARY

A method including: transmitting an instruction to a motive power supplyof an elastically deformable device to drive the elastically deformabledevice in accordance with a drive setting; measuring a force exerted onthe elastically deformable device with a sensor; outputting an observedvalue representative of the force; comparing the observed value with areference value corresponding with a predetermined force to be exertedon the elastically deformable device; and adjusting the drive settingbased on a determination that the observed value is outside of apredetermined range of the reference value.

The method may further include repeating the method beginning at themeasuring of the force.

The method may be provided so that the adjusting of the drive settingincludes: increasing the drive setting based on a determination that theobserved value is less than a lower threshold of the predetermined rangeof the reference value, decreasing the drive setting based on adetermination that the observed value is greater than an upper thresholdof the predetermined range of the reference value, and maintaining thedrive setting based on a determination that the observed value isgreater than or equal to the lower threshold and less than or equal tothe upper threshold.

The method may be provided so that the motive power supply includes amotor, the elastically deformable device includes a cable, the forceincludes tension on the cable, and the sensor includes a potentiometer.

The method may be provided so that the reference value is set at zerobased on detection of a desired tension of the cable.

The method may be provided so that the drive setting corresponds with amotor force exerted by the motor on the cable sufficient to maintain thepotentiometer within the predetermined range of the reference value.

The method may be provided so that the cable is a steering cable for aborescope.

The method may be provided so that the motive power supply is one fromthe group consisting of a servo, a micromotor, a linear motor, a leadscrew motor, a pneumatic actuator, a solenoid, shape memory alloys, adielectric actuator, a polymer elastic actuator, a piezo-electric motor,and a stepper, and wherein the sensor is one from the group consistingof a Hall effect sensor, a photo-interrupt sensor, a rotary encodersensor, a force transducer, an optical sensor, a linear inductionsensor, and a digital sensor with optical encoding.

The method may be provided so that the measuring, outputting, comparing,and adjusting are performed on a timed schedule of once per 10 ms.

A system, including: at least one processor and a memory storing atleast one program for execution by the at least one processor, the atleast one program including instructions, which when executed by the atleast one processor cause the at least one processor to performoperations including: transmitting an instruction to a motive powersupply of an elastically deformable device to drive the elasticallydeformable device in accordance with a drive setting; measuring a forceexerted on the elastically deformable device with a sensor; outputtingan observed value representative of the force; comparing the observedvalue with a reference value corresponding with a predetermined force tobe exerted on the elastically deformable device; and adjusting the drivesetting based on a determination that the observed value is outside of apredetermined range of the reference value.

The system may further include: an elastically deformable device; amotive power supply configured to drive the elastically deformabledevice; and a sensor configured to quantify the force exerted on theelastically deformable device.

The system may further include repeating the operations beginning at themeasuring of the force.

The system may be provided so that the adjusting of the drive settingincludes: increasing the drive setting based on a determination that theobserved value is less than a lower threshold of the predetermined rangeof the reference value, decreasing the drive setting based on adetermination that the observed value is greater than an upper thresholdof the predetermined range of the reference value, and maintaining thedrive setting based on a determination that the observed value isgreater than or equal to the lower threshold and less than or equal tothe upper threshold.

The system may be provided so that the motive power supply includes amotor, the elastically deformable device includes a cable, the forceincludes tension on the cable, and the sensor includes a potentiometer.

The system may be provided so that the reference value is set at zerobased on detection of a desired tension of the cable.

The system may be provided so that the drive setting corresponds with amotor force exerted by the motor on the cable sufficient to maintain thepotentiometer within the predetermined range of the reference value.

The system may be provided so that the cable is a steering cable for aborescope.

The system may be provided so that the motive power supply is one fromthe group consisting of a servo, a micromotor, a linear motor, a leadscrew motor, a pneumatic actuator, a solenoid, shape memory alloys, adielectric actuator, a polymer elastic actuator, a piezo-electric motor,and a stepper, and wherein the sensor is one from the group consistingof a Hall effect sensor, a photo-interrupt sensor, a rotary encodersensor, a force transducer, an optical sensor, a linear inductionsensor, and a digital sensor with optical encoding.

The system may be provided so that the measuring, outputting, comparing,and adjusting are performed on a timed schedule of once per 10 ms.

A non-transitory computer-readable storage medium storing at least oneprogram, which when executed by at least one processor and a memorystoring the at least one program cause the at least one processor toperform operations including: transmitting an instruction to a motivepower supply of an elastically deformable device to drive theelastically deformable device in accordance with a drive setting;measuring a force exerted on the elastically deformable device with asensor; outputting an observed value representative of the force;comparing the observed value with a reference value corresponding with apredetermined force to be exerted on the elastically deformable device;and adjusting the drive setting based on a determination that theobserved value is outside of a predetermined range of the referencevalue.

The non-transitory computer-readable storage medium may further includerepeating the operations beginning at the measuring of the force.

The non-transitory computer-readable storage medium may be provided sothat the adjusting of the drive setting includes: increasing the drivesetting based on a determination that the observed value is less than alower threshold of the predetermined range of the reference value,decreasing the drive setting based on a determination that the observedvalue is greater than an upper threshold of the predetermined range ofthe reference value, and maintaining the drive setting based on adetermination that the observed value is greater than or equal to thelower threshold and less than or equal to the upper threshold.

The non-transitory computer-readable storage medium may be provided sothat the motive power supply includes a motor, the elasticallydeformable device includes a cable, the force includes tension on thecable, and the sensor includes a potentiometer.

The non-transitory computer-readable storage medium may be provided sothat the reference value is set at zero based on detection of a desiredtension of the cable.

The non-transitory computer-readable storage medium may be provided sothat the drive setting corresponds with a motor force exerted by themotor on the cable sufficient to maintain the potentiometer within thepredetermined range of the reference value.

The non-transitory computer-readable storage medium may be provided sothat the cable is a steering cable for a borescope.

The non-transitory computer-readable storage medium may be provided sothat the motive power supply is one from the group consisting of aservo, a micromotor, a linear motor, a lead screw motor, a pneumaticactuator, a solenoid, shape memory alloys, a dielectric actuator, apolymer elastic actuator, a piezo-electric motor, and a stepper, andwherein the sensor is one from the group consisting of a Hall effectsensor, a photo-interrupt sensor, a rotary encoder sensor, a forcetransducer, an optical sensor, a linear induction sensor, and a digitalsensor with optical encoding.

The non-transitory computer-readable storage medium may be provided sothat the measuring, outputting, comparing, and adjusting are performedon a timed schedule of once per 10 ms.

These and other capabilities of the disclosed subject matter will bemore fully understood after a review of the following figures, detaileddescription, and claims.

DESCRIPTION OF DRAWINGS

These and other features will be more readily understood from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a schematic diagram of a system for adjusting a force exertedon an elastically deformable device;

FIG. 2 is a schematic depiction of a computer device or system includingat least one processor and a memory storing at least one program forexecution by the at least one processor;

FIG. 3 is a process diagram illustrating a method of adjusting a forceexerted on an elastically deformable device;

FIG. 4 is a process diagram illustrating conditions of an adjusting stepof the method of adjusting the force exerted on the elasticallydeformable device;

FIG. 5 is a perspective view of a system according to one exemplaryembodiment; and

FIG. 6 is a perspective view of a system according to another exemplaryembodiment.

It is noted that the drawings are not necessarily to scale. The drawingsare intended to depict only typical aspects of the subject matterdisclosed herein, and therefore should not be considered as limiting thescope of the disclosure. The structures, systems, devices, and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary embodiments and that the scope ofthe present invention is defined solely by the claims.

DETAILED DESCRIPTION

Over time, conventional borescopes develop cable slack as a product ofinsertion tube compression and cable stretch. As the slack develops,there becomes a point where motors, which have a limited stroke, cannottake up the extra cable. As a result, articulation and responsiveness ofthe borescope are lost over time. To overcome these problems, a sensoris attached to a steering cable that senses when the cable is taut.Feedback from the sensor is used by a steering system to determine whento utilize more stroke as cable slack develops. The steering systemeffectively adapts over time and extends the useful life of the system.

With conventional borescopes, a motor having a stroke of +/−0.20 in to0.50 in (5.08 mm to 12.7 mm) was typical. A motor capable of generatingmore stroke may be provided. A sensor may be provided configured to sendsignals to a processor to determine when the motor should use morestroke over time.

Since cable slack develops over relatively long periods of time (e.g.,in extreme conditions, slack may start to occur around 6 months; withlight use, slack may take several years or longer to develop), atinstallation, a motor may require a relatively low amount of stroke(e.g., on the order of +/−0.20″ to 0.50″ (5.08 mm to 12.7 mm)). Also,the slack problem is more pronounced with relatively long cables.Typical borescopes cables are about 6.56 ft to 32.8 ft (2 m to 10 m) inlength. Slack is more noticeable at, for example, 14.8 ft (4.5 m) orlonger compared to 6.56 ft (2 m). Slack develops when the cablespermanently stretch and the insertion tube compresses over time withuse.

To compensate for differences over time, including the slack problem,the motor may be provisioned at installation with a relatively largeamount of potential stroke to adjust to changes in cable slack overtime. In some embodiments for borescope applications, the stroke of themotor may be on the order of +/−0.45 in to 1.00 in (11.43 mm to 25.4mm), an increase of approximately 50% to 100% relative to conventionalmotors. Other suitable motors may be employed, depending on theapplication. In relatively larger scale applications, the stroke of themotor may be on the order of +/−2.20 in to 10.50 in (55.88 mm to 266.7mm).

The system monitors and determines when to utilize additional amounts ofstroke over time. A mechanical device may be used to couple the steeringcable system to a potentiometer. The potentiometer may be configured tocalibrate a “zero” position for each direction. The sensor orpotentiometer may utilize sensing technologies including Hall effect,linear induction, optical, digital with optical encoding, and the like.The motor may be configured to turn until the cable moves thepotentiometer to the zero position. At this point, at the zero position,all stroke that is used is “useful stroke”, i.e., stroke that moves thebending neck. Over time, as slack develops, more and more stroke isrequired to reach the zero position. The sensors may be configured todetect increasing (or decreasing) slack, and the motors may beconfigured to activate to adjust the system until the potentiometerreturns to the zero position.

In some embodiments, at initial use of a borescope, a camera may beprovided in line with an insertion tube, which is a home position forthe camera. In the home position, a potentiometer (e.g., potentiometer100, FIGS. 5 and 6 ) is provided at a nominal center position, and acable slack is either zero or equally distributed between two cables. Asthe camera is steered away from center, tension increases on one cablewhile the other cable becomes slack. As slack occurs, a block (e.g.,block 150, FIG. 6 ) with attached cable sheath terminators move upfollowing the cable in tension, which results in the potentiometermoving off nominal center. The camera may be moved in the oppositedirection, and the block will begin to move toward the previously slackcable when the slack is taken up. The potentiometer senses the slack inthe cable. A system (e.g., system 10, FIG. 1 ) receives data from thepotentiometer, and processes the received data to compensate for thecable slack. As shown, for example, in FIG. 5 , a rotary follower androtary potentiometer may be used.

In one exemplary implementation, as shown in FIG. 1 , a system 10 foradjusting a force exerted is provided. The system 10 may include anelastically deformable device 200. The elastically deformable device 200may be a cable, a steering cable for a borescope, a linkage, a chain, astring, a rope, a fiber, and the like. The system 10 may include amotive power supply 300 configured to drive the elastically deformabledevice 200. For the motive power supply 300, various motors may be usedincluding a servo, a micromotor, a linear motor, a lead screw motor, apneumatic actuator, a solenoid, shape memory alloys, a dielectric orpolymer elastic actuator, a piezo-electric motor, a stepper, and thelike. The motive power supply 300 may be directly connected to theelastically deformable device 200 or indirectly connected to theelastically deformable device 200 via a connecting structure 250.

The system 10 may include a sensor 100. The sensor 100 may be configuredto quantify a force exerted on the elastically deformable device 200.The force may be tension, compression, torque, and the like. For thesensor 100, various sensors may be used including a Hall effect sensor,a photo-interrupt sensor, a rotary encoder sensor, a force transducerand an optical sensor. The sensor may be integrated into the motivepower supply 300. The sensor 100 may be provided separately from themotive power supply 300, as illustrated in FIG. 1 . The sensor 100 maybe installed directly on the elastically deformable device 200. Thesensor 100 may be indirectly connected to the elastically deformabledevice 200 via a connecting structure 150. The system 10 may include acomputing device such as the device or system 500 illustrated in FIG. 2.

FIG. 2 depicts a device or system 500 comprising at least one processor530 and a memory 540 storing at least one program 550 for execution bythe at least one processor 530. In some implementations, the device orsystem 500 may further comprise a non-transitory computer-readablestorage medium 560 storing the at least one program 550 for execution bythe at least one processor 530 of the device or system 500. In someimplementations, the device or system 500 may further comprise at leastone input device 510, which may be configured to send or receiveinformation to or from any one from the group consisting of: an externaldevice (not shown), the at least one processor 530, the memory 540, thenon-transitory computer-readable storage medium 560, and at least oneoutput device 570. The at least one input device 510 may be configuredto wirelessly send or receive information to or from the external devicevia a means for wireless communication, such as an antenna 520, atransceiver (not shown) or the like.

In some implementations, the device or system 500 may further compriseat least one output device 570, which may be configured to send orreceive information to or from any one from the group consisting of: anexternal device (not shown), the at least one input device 510, the atleast one processor 530, the memory 540, and the non-transitorycomputer-readable storage medium 560. The at least one output device 570may be configured to wirelessly send or receive information to or fromthe external device via a means for wireless communication, such as anantenna 580, a transceiver (not shown) or the like.

The program 550 may include operations 600 (e.g., FIG. 3 ). Theoperations 600 may include a step 610 of transmitting an instruction toa motive power supply of the elastically deformable device to drive theelastically deformable device in accordance with a drive setting; a step620 of measuring the force exerted on the elastically deformable devicewith a sensor and outputting an observed value from the sensor; a step630 of comparing the observed value with a reference value correspondingwith a predetermined force to be exerted on the elastically deformabledevice; a step 640 of adjusting the drive setting based on the observedvalue; and a step 650 of returning to step 620. The step 640 may includea behavioral model of the insertion tube and cable system. The model mayrepresent the behavior of the cable and insertion tube under variouslevels of tension. The model may also take into account age or extremeusage of the steering mechanism or environmental conditions such astemperature and humidity.

One or more of steps 620, 630, 640 and 650 may be periodically performedon a timed schedule. For example, in some embodiments, steps 620, 630,640 and 650 may be periodically performed on the order of once per 10 ms(0.01 sec). In some embodiments, steps 620, 630, 640 and 650 may beperformed in shorter increments, longer increments or continuously. Oneor more operations 600 may be manually initiated by a user of the system10.

As seen in FIG. 4 , step 640 may include a step 642, the observed valueis less than a lower threshold of the predetermined range of thereference value, increasing the drive setting, and/or step 644, theobserved value is greater than an upper threshold of the predeterminedrange of the reference value, decreasing the drive setting, and/or step646, the observed value is greater than or equal to the lower thresholdand less than or equal to the upper threshold, maintaining the drivesetting.

In some embodiments, the system may adjust the cables using a rotaryfollower (e.g., follower 150, FIG. 5 ) moved in increments of +/− 1/10of a degree (+/−0.1°). Finer and coarser adjustment increments may beused.

FIG. 5 illustrates an example of a system 20 including a servo 300. Theservo 300 may rotate a cam 250 configured to attach and pull cables 200.The cables 200 may rotate a follower 150. The follower 150 may becoupled to a rotary potentiometer 100.

FIG. 6 illustrates an example of a system 30 including a servo 300. Theservo 300 may rotate a cam 250 configured to attach and pull cables 200.The cables 200 may move a block 150. The block 150 may be coupled to aslide potentiometer 100.

Each of the system 20 and the system 30 may include one or more featuresof the system 10 (FIG. 1 ), the device or system 500 (FIG. 2 ), and theoperations 600 (FIG. 3 ), including the step 640 (FIG. 4 ).

As used herein, slack may be, for example, a lack of tension on a cable.The sensor may sense a lack of tension and the system may be configuredto respond to the detection of the lack of tension. Tension may bedetected using a potentiometer configured to measure tension or lack oftension in units of volts (V), or Ohms (Ω). The system may be configuredto detect improper pre-tensioning during manufacturing.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Although at least one exemplary embodiment is described as using aplurality of units to perform the exemplary process, it is understoodthat the exemplary processes may also be performed by one or pluralityof modules. Additionally, it is understood that the termcontroller/control unit may refer to a hardware device that includes amemory and a processor. The memory may be configured to store themodules and the processor may be specifically configured to execute saidmodules to perform one or more processes which are described furtherbelow.

The use of the terms “first”, “second”, “third” and so on, herein, areprovided to identify various structures, dimensions or operations,without describing any order, and the structures, dimensions oroperations may be executed in a different order from the stated orderunless a specific order is definitely specified in the context.

Approximating language, as used herein throughout the specification andclaims, may be applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about” and “substantially,” are not to be limited tothe precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value. Here and throughout the specification andclaims, range limitations may be combined and/or interchanged, suchranges are identified and include all the sub-ranges contained thereinunless context or language indicates otherwise.

Unless specifically stated or obvious from context, as used herein, theterm “about” is understood as within a range of normal tolerance in theart, for example within 2 standard deviations of the mean. “About” canbe understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%,0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear fromthe context, all numerical values provided herein are modified by theterm “about.”

Furthermore, control logic of the present disclosure may be embodied asnon-transitory computer readable media on a computer readable mediumcontaining executable program instructions executed by a processor,controller/control unit or the like. Examples of the computer readablemediums include, but are not limited to, ROM, RAM, compact disc(CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards andoptical data storage devices. The computer readable recording medium canalso be distributed in network coupled computer systems so that thecomputer readable media is stored and executed in a distributed fashion,e.g., by a telematics server or a Controller Area Network (CAN).

One or more aspects or features of the subject matter described hereinmay be realized in digital electronic circuitry, integrated circuitry,specially designed application specific integrated circuits (ASICs),field programmable gate arrays (FPGAs) computer hardware, firmware,software, and/or combinations thereof. These various aspects or featuresmay include embodiment in one or more computer programs that areexecutable and/or interpretable on a programmable system including atleast one programmable processor, which may be special or generalpurpose, coupled to receive data and instructions from, and to transmitdata and instructions to, a storage system, at least one input device,and at least one output device. The programmable system or computingsystem may include clients and servers. A client and server aresubstantially remote from each other and typically interact through acommunication network. The relationship of client and server arises byvirtue of computer programs running on the respective computers andhaving a client-server relationship to each other.

These computer programs, which may also be referred to as programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and may beimplemented in a high-level procedural language, an object-orientedprogramming language, a functional programming language, a logicalprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium may storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid-state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium may alternativelyor additionally store such machine instructions in a transient manner,such as for example as would a processor cache or other random accessmemory associated with one or more physical processor cores.

To provide for interaction with a user, one or more aspects or featuresof the subject matter described herein may be implemented on a computerhaving a display device, such as for example a cathode ray tube (CRT) ora liquid crystal display (LCD) or a light emitting diode (LED) monitorfor displaying information to the user and a keyboard and a pointingdevice, such as for example a mouse or a trackball, by which the usermay provide input to the computer. Other kinds of devices may be used toprovide for interaction with a user as well. For example, feedbackprovided to the user may be any form of sensory feedback, such as forexample visual feedback, auditory feedback, or tactile feedback; andinput from the user may be received in any form, including acoustic,speech, or tactile input. Other possible input devices include touchscreens or other touch-sensitive devices such as single or multi-pointresistive or capacitive trackpads, voice recognition hardware andsoftware, optical scanners, optical pointers, digital image capturedevices and associated interpretation software, and the like.

In the descriptions above and in the claims, phrases such as “at leastone of” or “one or more of” may occur followed by a conjunctive list ofelements or features. The term “and/or” may also occur in a list of twoor more elements or features. Unless otherwise implicitly or explicitlycontradicted by the context in which it is used, such a phrase isintended to mean any of the listed elements or features individually orany of the recited elements or features in combination with any of theother recited elements or features. For example, the phrases “at leastone of A and B;” “one or more of A and B;” and “A and/or B” are eachintended to mean “A alone, B alone, or A and B together.” A similarinterpretation is also intended for lists including three or more items.For example, the phrases “at least one of A, B, and C;” “one or more ofA, B, and C;” and “A, B, and/or C” are each intended to mean “A alone, Balone, C alone, A and B together, A and C together, B and C together, orA and B and C together.” In addition, use of the term “based on,” aboveand in the claims is intended to mean, “based at least in part on,” suchthat an unrecited feature or element is also permissible.

The subject matter described herein may be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. The embodiments set forth in the foregoing description donot represent all embodiments consistent with the subject matterdescribed herein. Instead, they are merely some examples consistent withaspects related to the described subject matter. Although a fewvariations have been described in detail above, other modifications oradditions are possible. In particular, further features and/orvariations may be provided in addition to those set forth herein. Forexample, the embodiments described above may be directed to variouscombinations and subcombinations of the disclosed features and/orcombinations and subcombinations of several further features disclosedabove. In addition, the logic flows depicted in the accompanying figuresand/or described herein do not necessarily require the particular ordershown, or sequential order, to achieve desirable results. Otherembodiments may be within the scope of the following claims.

What is claimed is:
 1. A method comprising: transmitting an instructionto a motive power supply of an elastically deformable device to drivethe elastically deformable device in accordance with a drive setting;measuring a force exerted on the elastically deformable device with asensor; outputting an observed value representative of the force;comparing the observed value with a reference value corresponding with apredetermined force to be exerted on the elastically deformable device;determining, based on the comparing, that the elastically deformabledevice has been permanently stretched based on the observed value beingoutside of a predetermined range of the reference value; and adjustingthe drive setting based on the observed value.
 2. The method of claim 1,further comprising repeating the method beginning at the measuring ofthe force.
 3. The method of claim 1, wherein the adjusting of the drivesetting includes: increasing the drive setting based on a determinationthat the observed value is less than a lower threshold of thepredetermined range of the reference value, decreasing the drive settingbased on a determination that the observed value is greater than anupper threshold of the predetermined range of the reference value, andmaintaining the drive setting based on a determination that the observedvalue is greater than or equal to the lower threshold and less than orequal to the upper threshold.
 4. The method of claim 1, wherein themotive power supply includes a motor, the elastically deformable deviceincludes a cable, the force includes tension on the cable, and thesensor includes a potentiometer.
 5. The method of claim 4, wherein thereference value is set at zero based on detection of a desired tensionof the cable.
 6. The method of claim 4, wherein the drive settingcorresponds with a motor force exerted by the motor on the cablesufficient to maintain the potentiometer within the predetermined rangeof the reference value.
 7. The method of claim 4, wherein the cable is asteering cable for a borescope.
 8. The method of claim 1, wherein themotive power supply is one from the group consisting of a servo, amicromotor, a linear motor, a lead screw motor, a pneumatic actuator, asolenoid, shape memory alloys, a dielectric actuator, a polymer elasticactuator, a piezo-electric motor, and a stepper, and wherein the sensoris one from the group consisting of a Hall effect sensor, aphoto-interrupt sensor, a rotary encoder sensor, a force transducer, anoptical sensor, a linear induction sensor, and a digital sensor withoptical encoding.
 9. The method of claim 1, wherein the measuring,outputting, comparing, and adjusting are performed on a timed scheduleof once per 10 ms.
 10. A system, comprising: at least one processor anda memory storing at least one program for execution by the at least oneprocessor, the at least one program including instructions, which whenexecuted by the at least one processor cause the at least one processorto perform operations comprising: transmitting an instruction to amotive power supply of an elastically deformable device to drive theelastically deformable device in accordance with a drive setting;measuring a force exerted on the elastically deformable device with asensor; outputting an observed value representative of the force;comparing the observed value with a reference value corresponding with apredetermined force to be exerted on the elastically deformable device;determining, based on the comparing, that the elastically deformabledevice has been permanently stretched based on the observed value beingoutside of a predetermined range of the reference value; and adjustingthe drive setting based the observed value.
 11. The system of claim 10,the system further comprising: the elastically deformable device; amotive power supply configured to drive the elastically deformabledevice; and a sensor configured to quantify the force exerted on theelastically deformable device.
 12. The system of claim 10, furthercomprising repeating the operations beginning at the measuring of theforce.
 13. The system of claim 10, wherein the adjusting of the drivesetting includes: increasing the drive setting based on a determinationthat the observed value is less than a lower threshold of thepredetermined range of the reference value, decreasing the drive settingbased on a determination that the observed value is greater than anupper threshold of the predetermined range of the reference value, andmaintaining the drive setting based on a determination that the observedvalue is greater than or equal to the lower threshold and less than orequal to the upper threshold.
 14. The system of claim 10, wherein themotive power supply includes a motor, the elastically deformable deviceincludes a cable, the force includes tension on the cable, and thesensor includes a potentiometer.
 15. The system of claim 14, wherein thereference value is set at zero based on detection of a desired tensionof the cable.
 16. The system of claim 14, wherein the drive settingcorresponds with a motor force exerted by the motor on the cablesufficient to maintain the potentiometer within the predetermined rangeof the reference value.
 17. The system of claim 14, wherein the cable isa steering cable for a borescope.
 18. The system of claim 10, whereinthe motive power supply is one from the group consisting of a servo, amicromotor, a linear motor, a lead screw motor, a pneumatic actuator, asolenoid, shape memory alloys, a dielectric actuator, a polymer elasticactuator, a piezo-electric motor, and a stepper, and wherein the sensoris one from the group consisting of a Hall effect sensor, aphoto-interrupt sensor, a rotary encoder sensor, a force transducer, anoptical sensor, a linear induction sensor, and a digital sensor withoptical encoding.
 19. The system of claim 10, wherein the measuring,outputting, comparing, and adjusting are performed on a timed scheduleof once per 10 ms.
 20. A non-transitory computer-readable storage mediumstoring at least one program, which when executed by at least oneprocessor and a memory storing the at least one program cause the atleast one processor to perform operations comprising: transmitting aninstruction to a motive power supply of an elastically deformable deviceto drive the elastically deformable device in accordance with a drivesetting; measuring a force exerted on the elastically deformable devicewith a sensor; outputting an observed value representative of the force;comparing the observed value with a reference value corresponding with apredetermined force to be exerted on the elastically deformable device;determining, based on the comparing, that the elastically deformabledevice has been permanently stretched based on the observed value beingoutside of a predetermined range of the reference value; and adjustingthe drive setting based on the observed value.